<!DOCTYPE html>
<html>
	<head>
		<title>Threejs中使用astar(A*)算法寻路导航</title>
		<script type="text/javascript" src="libs/three.js"></script>
		<script type="text/javascript" src="libs/OrbitControls.js"></script>
		<script type="text/javascript" charset="UTF-8" src="libs/Tween.min.js"></script>
		<script type="text/javascript" src="libs/astar.js"></script>
		<style>
			body {
				margin: 0;
				overflow: hidden;
			}
		</style>
	</head>
	<body>
		<div id="dom"></div>
		<script type="text/javascript">
			var camera;
			var renderer;
			var clock = new THREE.Clock();
			var length = 36;
			var ws = 2;
			var graph = [];
			var mesh = [];
			var resultArray = new Array();
			var isCaculate = false;

			function init() {
				// 创建一个场景，它将包含我们所有的元素，如物体，相机和灯光。
				var scene = new THREE.Scene();

				var urls = [
					'assets/textures/posx.jpg',
					'assets/textures/negx.jpg',
					'assets/textures/posy.jpg',
					'assets/textures/negy.jpg',
					'assets/textures/posz.jpg',
					'assets/textures/negz.jpg'
				];

				var cubeLoader = new THREE.CubeTextureLoader();
				scene.background = cubeLoader.load(urls);

				// 创建一个摄像机，它定义了我们正在看的地方
				camera = new THREE.PerspectiveCamera(40, window.innerWidth / window.innerHeight, 0.1, 1000);
				// 将摄像机对准场景的中心
				camera.position.x = 60;
				camera.position.y = 35;
				camera.position.z = 60;
				camera.lookAt({
					x: 0,
					y: 5,
					z: -20
				});
				var orbit = new THREE.OrbitControls(camera);
				orbit.target = camera.position;
				orbit.update();

				// 创建一个渲染器并设置大小，WebGLRenderer将会使用电脑显卡来渲染场景
				// initialize basic renderer
				renderer = new THREE.WebGLRenderer();
				renderer.setSize(window.innerWidth, window.innerHeight);

				// 将平面添加到场景中
				var plane = createPlaneGeometryBasicMaterial();
				scene.add(plane);

				// 在屏幕上显示坐标轴
				var axes = new THREE.AxesHelper(100);
				scene.add(axes);

				// var trackballControls = initTrackballControls(camera, renderer);

				scene.add(new THREE.AmbientLight(0x666666));


				var ambientLight = new THREE.AmbientLight("#ffffff", 1);
				scene.add(ambientLight);
				document.getElementById("dom").appendChild(renderer.domElement);

				initGround();
				initGrid();
				initGridArr();

				// 启动动画
				renderScene();

				// 创建一个地面
				function createPlaneGeometryBasicMaterial() {
					var textureLoader = new THREE.TextureLoader();
					var cubeMaterial = new THREE.MeshStandardMaterial({
						map: textureLoader.load("assets/textures/cd.jpg"),
					});
					cubeMaterial.map.wrapS = THREE.RepeatWrapping;
					cubeMaterial.map.wrapT = THREE.RepeatWrapping;
					cubeMaterial.map.repeat.set(18, 18)
					// 创建地平面并设置大小
					var planeGeometry = new THREE.PlaneGeometry(500, 500);
					var plane = new THREE.Mesh(planeGeometry, cubeMaterial);

					// 设置平面位置并旋转
					plane.rotation.x = -0.5 * Math.PI;
					plane.position.x = 0;
					plane.position.z = 0;
					return plane;
				}

				// 初始化线路
				function initLine(pArr) {
					var points = [];
					var geometry = new THREE.Geometry();
					for (var i = 0; i < pArr.length; i++) {
						var randomX = pArr[i].x;
						var randomY = pArr[i].y;
						var randomZ = pArr[i].z;
						var vector = new THREE.Vector3(randomX, randomY, randomZ);
						geometry.vertices.push(vector);
						points.push(vector);
					}
					var material = new THREE.LineBasicMaterial({
						color: 0x0000FF
					});
					var line = new THREE.Line(geometry, material);
					scene.add(line);
					return points;
				}

				// 绘制路网
				function initGround() {
					var geometry = new THREE.Geometry();
					geometry.vertices.push(new THREE.Vector3(0, 0, 0));
					geometry.vertices.push(new THREE.Vector3(length, 0, 0));

					for (var i = 0; i <= length / ws; i++) {
						var material = new THREE.LineBasicMaterial({
							color: 0x808080
						});
						var line = new THREE.Line(geometry, material);
						line.position.z = i * ws;
						scene.add(line);

						var line = new THREE.Line(geometry, material);
						line.position.x = i * ws;
						line.position.z = length;
						line.rotation.y = 90 * Math.PI / 180;
						scene.add(line);
					}
				}

				// 初始化障碍物
				function initGrid() {
					for (var i = 0; i < length / ws; i++) {
						var nodeRow = [];
						for (var j = 0; j < length / ws; j++) {
							var salt = Math.random() * 7;
							if (salt > 2) {
								nodeRow.push(1);
							} else {
								nodeRow.push(0);
							}
							if (salt <= 2) {
								var cube = new THREE.Mesh(new THREE.CubeGeometry(1, 1, 1), new THREE.MeshBasicMaterial({
									color: 0xC0C0C0
								}));
								let x = ws * j + ws / 2;
								let z = ws * i + ws / 2;
								cube.position.set(x, 1.2, z);
								scene.add(cube);
								mesh.push(cube);
							}
						}
						graph.push(nodeRow);
					}
				}

				function initGridArr() {
					for (var i = 0; i < length / ws; i++) {
						var nodeRow = [];
						for (var j = 0; j < length / ws; j++) {
							nodeRow.push(1);
						}
						graph.push(nodeRow);
					}
				}

				//计算路径
				function caculatePath(resultArray) {
					var maps = new Graph(graph); // 地图
					var startX = parseInt(resultArray[0].position.z / ws);
					var startY = parseInt(resultArray[0].position.x / ws);
					var endX = parseInt(resultArray[1].position.z / ws);
					var endY = parseInt(resultArray[1].position.x / ws);
					var start = maps.grid[startX][startY];
					var end = maps.grid[endX][endY];
					result = astar.search(maps, start, end);
					if (result.length == 0) {
						alert("无可到达路径");
						cleanSphere();
						return;
					}

					var nArr = [{
						x: resultArray[0].position.x,
						z: resultArray[0].position.z,
						y: 1.2
					}];
					for (var i = 0; i < result.length; i++) {
						let d = {
							x: result[i].y * ws + ws / 2,
							y: 1.2,
							z: result[i].x * ws + ws / 2,
						}
						nArr.push(d);
					}
					initLine(nArr);
				}

				//清除小球
				function cleanSphere() {
					let child = scene.children; //获取场景中的所有子对象
					for (var i = 0; i < child.length; i++) {
						if (child[i].geometry instanceof THREE.SphereGeometry) { //几何对象是球体几何
							scene.remove(child[i]); //从场景中移除
							i--;
						}
					}
					isCaculate = false;
				}

				//初始球体
				function initSphere(x, z) {
					if (isCaculate) {
						cleanSphere();
					}
					var geometry = new THREE.SphereGeometry(ws / 2, 30, 30); //球体几何
					var material = new THREE.MeshBasicMaterial({
						color: 0xffff00
					}); //网格基础材料

					if (resultArray.length == 0) {
						var sphere = new THREE.Mesh(geometry, material);
						sphere.position.x = x;
						sphere.position.y = 1;
						sphere.position.z = z;
						resultArray.push(sphere);
						scene.add(sphere);
					} else if (resultArray[0].position.x != x || resultArray[0].position.z != z) {
						var sphere = new THREE.Mesh(geometry, material);
						sphere.position.x = x;
						sphere.position.y = 1;
						sphere.position.z = z;
						resultArray.push(sphere);
						scene.add(sphere);
						caculatePath(resultArray);
						isCaculate = true;
						resultArray = new Array();
					}
				}

				// 拾取对象
				function pickupObjects(event) {
					// 点击屏幕创建一个向量
					var raycaster = new THREE.Raycaster();
					var vector = new THREE.Vector2((event.clientX / window.innerWidth) * 2 - 1, -(event.clientY / window
						.innerHeight) * 2 + 1);
					var fxl = new THREE.Vector3(0, 1, 0);
					var groundplane = new THREE.Plane(fxl, 0);
					raycaster.setFromCamera(vector, camera);
					var ray = raycaster.ray;
					let intersects = ray.intersectPlane(groundplane);
					let x = intersects.x;
					let z = intersects.z;

					if (x < 0 || z < 0 || length < z || length < x) {
						return;
					}

					var k, m;
					for (var i = 0; i < length; i += ws) {
						if (x >= i && x < i + ws) {
							k = i + ws / 2;
						}
					}
					for (var j = 0; j < length; j += ws) {
						if (z >= j && z < j + ws) {
							m = j + ws / 2;
						}
					}


					initSphere(k, m); //初始化球体
				}
				document.addEventListener('click', pickupObjects, false); //监听单击拾取对象初始化球体

				// 动画渲染
				var step = 5;

				function renderScene() {
					orbit.update();

					// 使用requestAnimationFrame函数进行渲染
					requestAnimationFrame(renderScene);
					renderer.render(scene, camera);
				}

				// 渲染的场景
				renderer.render(scene, camera);
			}
			window.onload = init;

			function onResize() {
				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();
				renderer.setSize(window.innerWidth, window.innerHeight);
			}
			// 监听调整大小事件
			window.addEventListener('resize', onResize, false);
		</script>
	</body>
</html>
